U.S. patent number 6,102,816 [Application Number 09/188,205] was granted by the patent office on 2000-08-15 for golf ball.
This patent grant is currently assigned to Spalding Sports Worlwide, Inc.. Invention is credited to Mark Binette, Dennis Nesbitt, Michael J. Sullivan.
United States Patent |
6,102,816 |
Sullivan , et al. |
August 15, 2000 |
Golf ball
Abstract
A golf ball having an outside diameter of at least 1.70 inches
which includes a core, an inner cover, or mantle, and an outside
cover. The mantle and the outer cover have a different Shore D
hardness. Dimples cover at least seventy percent of the outer
surface area of the ball. In one embodiment, the mantle has a Shore
D hardness between 50 and 60 and the cover has a Shore D hardness
of 65 or less with the mantle hardness being greater than the cover
hardness. In another embodiment, the mantle has a Shore D hardness
of 65 or less and the cover has a Shore D hardness between 50 and
60, with the cover hardness being greater than the mantle
hardness.
Inventors: |
Sullivan; Michael J. (Chicopee,
MA), Nesbitt; Dennis (Westfield, MA), Binette; Mark
(Ludlow, MA) |
Assignee: |
Spalding Sports Worlwide, Inc.
(Chicopee, MA)
|
Family
ID: |
22692178 |
Appl.
No.: |
09/188,205 |
Filed: |
November 9, 1998 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
|
887053 |
Jul 2, 1997 |
5833554 |
|
|
|
530851 |
Sep 20, 1995 |
5766098 |
|
|
|
171956 |
Dec 22, 1993 |
5503397 |
|
|
|
800198 |
Nov 27, 1991 |
5273287 |
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Current U.S.
Class: |
473/374; 473/377;
473/384 |
Current CPC
Class: |
A63B
37/0003 (20130101); A63B 37/0004 (20130101); A63B
37/12 (20130101); A63B 37/02 (20130101); A63B
37/0006 (20130101); A63B 37/0021 (20130101); A63B
37/0062 (20130101); A63B 37/008 (20130101); A63B
37/0083 (20130101); A63B 37/0031 (20130101) |
Current International
Class: |
A63B
37/00 (20060101); A63B 37/12 (20060101); A63B
37/02 (20060101); A63B 037/06 () |
Field of
Search: |
;473/374,377,384 |
References Cited
[Referenced By]
U.S. Patent Documents
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|
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5833554 |
November 1998 |
Sullivan et al. |
|
Primary Examiner: Passaniti; Sebastiano
Assistant Examiner: Gordon; Raeann
Attorney, Agent or Firm: Laubscher & Laubscher
Parent Case Text
This application is a continuation-in-part of U.S. patent
application Ser. No. 08/887,053 filed Jul. 2, 1997, now U.S. Pat.
No. 5,833,554 which is a continuation-in-part of U.S. patent
application Ser. No. 08/530,851 filed Sep. 20, 1995, now U.S. Pat.
No. 5,766,098 which is a division of U.S. patent application Ser.
No. 08/171,956 filed Dec. 22, 1993, now U.S. Pat. No. 5,503,397,
which is a continuation of U.S. patent application Ser. No.
07/800,198 filed Nov. 27, 1991, now U.S. Pat. No. 5,273,287.
Claims
What is claimed is:
1. A golf ball of improved playing characteristics, comprising
(a) a spherical core;
(b) a mantle layer surrounding said core and having a Shore D
hardness of 50 to 60;
(c) an outer cover layer surrounding said core and said mantle
layer, said cover layer having a Shore D hardness of 65 or less,
said mantle layer Shore D hardness being greater than said cover
layer Shore D hardness; and
(d) said cover layer containing a dimple pattern covering at least
65% of the surface of the ball, the ball having an outer diameter
of substantially 1.70 to 1.80 inches and a weight no greater than
1.62 ounces.
2. A golf ball of improved playing characteristics, comprising
(a) a spherical core;
(b) a mantle layer surrounding said core and having a Shore D
hardness of 65 or less;
(c) an outer cover layer surrounding said core and said mantle
layer, said cover layer having a Shore D hardness of 55 to 60 said
cover layer Shore D hardness being greater than said mantle layer
Shore D hardness; and
(d) said cover layer containing a dimple pattern covering at least
65% of the surface of the ball, the ball having an outer diameter
of substantially 1.70 to 1.80 inches and a weight no greater than
1.62 ounces .
Description
BACKGROUND OF THE INVENTION
This invention relates to golf balls. In particular, it relates to
a three-piece golf ball having playability characteristics which
are improved relative to state-of-the-art balls.
According to United States Golf Association (U.S.G.A.) rules, a
golf ball may not have a weight in excess of 1.620 ounces or a
diameter smaller than 1.680 inches. The initial velocity of
U.S.G.A. "regulation" balls may not exceed 250 feet per second with
a maximum tolerance of 2%. Initial velocity is measured on a
standard machine kept by the U.S.G.A. A projection on a wheel
rotating at a defined speed hits the test ball, and the length of
time it takes the ball to traverse a set distance after impact is
measured. U.S.G.A. regulations also require that a ball not travel
a distance greater than 280 yards when hit by the U.S.G.A. outdoor
driving machine under specified conditions. In addition to this
specification, there is a tolerance of plus 4% and a 2% tolerance
for test error.
These specifications limit how far a golf ball will travel when hit
in several ways. Increasing the weight of a golf ball tends to
increase the distance it will travel and lower the trajectory. A
ball having greater momentum is better able to overcome drag.
Reducing the diameter of the ball also has the effect of increasing
the distance it will travel when hit. This is believed to occur
primarily because a smaller ball has a smaller projected area and,
thus, a lower drag when traveling through the air. Increasing
initial velocity increases the distance the ball will travel.
The foregoing generalizations hold when the effect of size, weight,
or initial velocity is measured in isolation. Flight
characteristics (influenced by dimple pattern and ball rotation
properties), club head speed, radius of gyration, and diverse other
factors also influence the distance a ball will travel:
In the manufacture of top-grade golf balls for use by professional
golfers and amateur golf enthusiasts, the distance a ball will
travel when hit (hereinafter referred to as "distance") is an
important design criterion. Since the U.S.G.A. rules were
established, golf ball manufacturers have designed top-grade
U.S.G.A. regulation balls to be as close to the maximum weight,
minimum diameter, and maximum initial velocity as golf ball
technology will permit. The distance a ball will travel when hit
has, however, been improved by changes in raw materials and by
alterations in dimple configuration.
BRIEF DESCRIPTION OF THE PRIOR ART
Golf balls not conforming to U.S.G.A. specifications in various
respects have been made in the United States. Prior to the
effective date of the U.S.G.A. rules, balls of various weight,
diameters, and resiliencies were common. So-called "rabbit balls,"
which claim to exceed the U.S.G.A. initial velocity, have also been
offered for sale. Recently, oversized, overweight golf balls have
been on sale for use as golf teaching aids (see U.S. Pat. No.
4,201,384 to Barber).
Oversized golf balls are also disclosed in New Zealand Patent
192,618 dated Jan. 1, 1980, issued to a predecessor of the present
assignee. This patent discloses an oversized golf ball having a
diameter between 1.700 and 1.730 inches and an oversized core of
resilient material so as to increase the coefficient of
restitution. Additionally, the patent discloses that the ball
should include a cover having a thickness less than the cover
thickness of conventional ball. The patent has no disclosure as to
dimple size or the percentage of surface coverage by the
dimples.
Golf balls made by Spalding in 1915 were of a diameter ranging from
1.630 inches to 1.710 inches. While these balls had small shallow
dimples, they covered less than 50% of the surface of the ball.
Additionally, as the diameter of the ball increased, the weight of
the ball also increased.
Golf balls known as the LYNX JUMBO were also produced and sold in
October of 1979. This ball had a diameter of substantially 1.80
inches. The dimples on the LYNX JUMBO balls had 336 Atti-type
dimples with each dimple having a diameter of 0.147 inch and a
depth of 0.0148 inch. With this dimple arrangement, 56.02% of the
surface area of the ball was covered by the dimples. This ball met
with little or no commercial success.
Top-grade golf balls sold in the United States may be classified as
one of two types: two-piece or three-piece. The two-piece ball,
exemplified by the balls sold by Spalding Sports Worldwide under
the trademark TOP-FLITE, consists of a solid polymeric core and a
separately formed cover. The so-called three-piece ball,
exemplified by the balls sold under the trademark TITLEIST by the
Acushnet Company, consists of a liquid (e.g., TITLEIST TOUR 384) or
solid (e.g., TITLEIST DT) center, elastomeric thread windings about
the center, and a cover. Although the nature of the cover can, in
certain instances, make a significant contribution to the overall
coefficient of restitution and initial velocity of a ball (see, for
example, U.S. Pat. No. 3,819,768 to Molitor), the initial velocity
of two-piece and three-piece balls is determined mainly by the
coefficient of restitution of the core. The coefficient of
restitution of the core of wound balls can be controlled within
limits by regulating the winding tension and the thread and center
composition. With respect to two-piece balls, the coefficient of
restitution of the core is a function of the properties of the
elastomer composition from which it is made. Solid cores today are
typically molded using polybutadiene elastomers mixed with acrylate
or methacrylate metal slats. High-density fillers such as zinc
oxide are included in the core material in order to achieve the
maximum U.S.G.A. weight limit.
Improvements in cover and core material formulations and changes in
dimple patterns have more or less continually improved golf ball
distance for the last 20 years. Top-grade golf balls, however, must
meat several other important design criteria. To successfully
compete in today's golf market, a golf ball should be resistant to
cutting and must be finished well; it should hold a line in putting
and should have good click and feel. With a well-designed ball,
experienced players can better execute shots involving draw, fade,
or abrupt stops, as the situation dictates.
SUMMARY OF THE INVENTION
The golf ball of the present invention provides an improvement over
previously proposed oversized golf balls. The present ball has an
outside diameter of at least 1.70 inches and comprised a core, an
inner cover, or mantle, and an outer cover. The mantle and the
outer cover have a different Shore D hardness. Dimples cover at
least seventy percent of the outer surface area of the ball.
BRIEF DESCRIPTION OF THE FIGURES
Other objects and advantages of the invention will become apparent
from a study of the following specification, when viewed in the
light of the accompanying drawing, in which:
FIGS. 1a-1d are partially broken-away views of first, second,
third, and fourth embodiments, respectively, of the improved golf
ball of the present invention;
FIG. 2 illustrates dimple diameter and depth measurements; and
FIGS. 3, 4, and 5 disclose different dimple patterns, respectively,
which may be used with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The following description relates to several particular embodiments
of the golf ball of the present invention, but the concept of the
present invention is not to be limited to such embodiments. It
should be noted that all of the specific dimensions set forth have
a manufacturing tolerance of .+-.0.05%. Additionally, all the balls
have a weight no greater than 1.62 ounces.
In each of the embodiments of FIGS. 1a-1d, the golf ball 11 of the
invention includes a core 13, a mantle layer 15 which covers the
core, and an outer cover layer 17 which covers the mantle layer.
Dimples 19 are provided in the surface of the cover.
The ball 11 has an outer diameter D, the core layer 13 has a
diameter C,
the mantle layer 15 has a thickness TM and the cover layer has a
thickness TC.
The invention is characterized by forming the mantle and cover
layers from materials having different Shore D hardness. As used
herein, Shore D hardness of the mantle and cover layers is measured
generally in accordance with ASTM D-2240, except that the
measurements are made on the curved surface of a molded mantle or
cover, rather than on a plaque. Furthermore, the Shore D hardness
of the mantle layer is measured while the mantle layer remains over
the core and the Shore D hardness of the cover layer remains over
the mantle layers. When a hardness measurement is made on a dimpled
cover layer, the Shore D hardness is measured at a land area of the
dimpled cover layer.
The resilience of coefficient of restitution (COR) of a golf ball
is the constant "e," which is the ratio of the relative velocity of
an elastic sphere after direct impact to that before impact. As a
result, the COR ("e") can vary from 0 to 1, with 1 being equivalent
to a perfectly or completely elastic collision and 0 being
equivalent to a perfectly or completely inelastic collision.
COR, along with additional factors such as club head speed, club
head mass, ball weight, ball size and density, spin rate, angle of
trajectory and surface configuration (i.e., dimple pattern and area
of dimple coverage) as well as environment conditions (e.g.,
temperature, moisture, atmospheric pressure, wind, etc.) generally
determine the distance a ball will travel when hit. Along this
line, the distance a golf ball will travel under controlled
environment conditions is a function of the speed and mass of the
club and size, density and resilience (COR) of the ball, and other
factors. The initial velocity of the club, the mass of the club,
and the angle of the ball's departure are essentially provided by
the golfer upon striking. Since club head club head mass, the angle
of trajectory, and environmental condition are determines
controllable by golf ball producers and the ball size and weight
are set by the U.S.G.A., these are not factors of concern among
golf ball manufacturers. The factors or determinants of interest
with respect to improved distance are generally the coefficient of
restitution (COR) and the surface configuration (dimple pattern,
ratio of land area to dimple area, etc.) of the ball.
The COR is solid core balls is a function of the composition of the
molded core and of the cover. The molded core and/or cover may be
comprised of one or more layers such as in multi-layered balls. In
balls containing a wound core (i.e., balls comprising a liquid or
solid center, elastic windings, and a cover), the coefficient of
restitution is a function of not only the composition of the center
and cover, but also the composition and tension of the elastomeric
windings. As in the solid core balls, the center and cover of a
wound core ball may also consist of one or more layers.
The coefficient of restitution is the ratio of the outgoing
velocity to the incoming velocity. In the examples of this
application, the coefficient of restitution of a golf ball was
measured by propelling a ball horizontally at a speed of 125.+-.5
feet per second (fps) and corrected to 125 fps against a generally
vertical, hard, flat steel plate and measuring the ball's incoming
and outgoing velocity electronically. Speeds were measured with a
pair of Oehler Mark 55 ballistic screens available from Oehler
Research, Inc., P.O. Box 9135, Austin, Tex. 78766, which provide a
timing pulse when an object passes through them: The screens were
separated by 36" and are located 25.25" and 61.25" from the rebound
wall. The ball speed was measured by timing the pulses from screen
1 to screen 2 on the way into the rebound wall (as the average
speed of the ball over 36"), and then the exit speed was timed from
screen 2 to screen 1 over the same distance. The rebound wall was
tilted 2 degrees from a vertical plane to allow the ball to rebound
slightly downward in order to miss the edge of the cannon that
fired it. The rebound wall is solid steel 2.0 inches thick.
As indicated above, the incoming speed should be 125.+-.5 fps but
corrected to 125 fps. The correction between COR and forward or
incoming speed has been studied and a correction has been made over
the .+-.5 fps range so that the COR is reported as if the ball had
an incoming speed of exactly 125.0 fps.
The coefficient of restitution must be carefully controlled in all
commercial golf balls if the ball is to be within the specification
regulated by the United States Golf Association (U.S.G.A.). As
mentioned to some degree above, the U.S.G.A. standards indicate
that a "regulation" ball cannot have an initial velocity exceeding
255 feet per second in an atmosphere of 75 F. when tested in a
U.S.G.A. machine. Since the coefficient of restitution of a ball is
related to the ball's initial velocity, it is highly desirable to
produce a ball having sufficiently high coefficient of restitution
to closely approach the U.S.G.A. limit on initial velocity, while
having an ample degree of softness (i.e., hardness) to produce
enhanced playability (i.e., spin, etc).
PGA compression is another important property involved in the
performance of a golf ball. The compression of the ball can affect
the playability of the ball on striking and the sound or "click"
produced. Similarly, compression can effect the "feel" of the ball
(i.e., hard or soft responsive feel), particularly in chipping and
putting.
Moreover, while compression itself has little bearing on the
distance performance of a ball, compression can affect the
playability of the ball on striking. The degree of compression of a
ball against the club face and the softness of the cover strongly
influences the resultant spin rate. Typically, a softer cover will
produce a higher spin rate than a harder cover. Additionally, a
harder core will produce a higher spin rate than a softer core.
This is because at impact a hard core serves to compress the cover
of the ball against the face of the club to a much greater degree
than a soft core, thereby resulting in more "grab" of the ball on
the clubface and subsequent higher spin rates. In effect, the cover
is squeezed between the relatively incompressible core and
clubhead. When a softer core is used, the cover is under much less
compressive stress than when a harder core is used and therefore
does not contact the clubface as intimately. This results in lower
spin rates.
The term "compression" utilized in the golf ball trade generally
defines the overall deflection that a golf ball undergoes when
subjected to a compressive load. For example, PGA compression
indicates the amount of change in a golfball's shape upon striking.
The development of solid core technology in two piece balls has
allowed for much more precise control of compression in comparison
to thread wound three-piece balls. This is because in the
manufacture of solid core balls, the amount of deflection or
deformation is precisely controlled by the chemical formula used in
making the cores. This differs from wound three-piece balls wherein
compression is controlled in part by the winding process of the
elastic thread. Thus, two-piece and multilayer solid core balls
exhibit much more consistent compression readings than balls having
wound cores such as the thread wound three-piece balls.
In the past, PGA compression related to a scale of from 0 to 200
given to a golf ball. The lower the PGA compression value, the
softer the feel of the ball upon striking. In practice, tournament
quality balls have compression ratings around 70-110, preferably
around 80 to 100.
In determining PGA compression using the 0-200 scale, a standard
force is applied to the external surface of the ball. A ball which
exhibits no deflection (0.0 inches in deflection) is rated 200 and
a ball which deflects 2/10th of an inch (0.2 inches) is rated 0,
Every change of 0.001 of an inch represents a 1 point drop in
compression. Consequently, a ball which deflects 0.1 inches
(100.times.0.001 inches) has a PGA compression value of 100 (i.e.,
200-100) and a ball which deflects 0.110 inches (110.times.0.001
inches) has a PGA compression of 90 (i.e., 200-110).
In order to assist in the determination of compression, several
devices have been employed by the industry. For example, PGA
compression is determined by an apparatus fashioned in the form of
a small press with an upper and lower anvil. The upper anvil is at
rest against a 200-pound die spring, and the lower anvil is movable
through 0.300 inches by means of a crank mechanism. In its open
position the gap between the anvils is 1.780 inches, allowing a
clearance of 0.100 inches for insertion of the ball. As the lower
anvil is raised by the crank, it compresses the ball against the
upper anvil, such compression occurring during the last 0.200
inches of stroke of the lower anvil, the ball then loading the
upper anvil which in turn loads the spring. The equilibrium point
of the upper anvil is measured by a dial micrometer if the anvil is
deflected by the ball more than 0.100 inches (less deflection is
simply regarded as zero compression) and the reading on the
micrometer dial is referred to as the compression of the ball. In
practice, tournament quality balls have compression ratings around
80 to 100 which means that the upper anvil was deflected a total of
0.120 to 0.100 inches.
An example to determine PGA compression can be shown by utilizing a
golf ball compression tester produced by Atti Engineering
Corporation of Newark, N.J. The value obtained by this tester
relates to an arbitrary value expressed by a number which may range
from 0 to 100, although a value of 200 can be measured as indicated
by two revolutions of the dial indicator on the apparatus. The
value obtained defines the deflection that a golf ball undergoes
when subjected to compressive loading. The Atti test apparatus
consists of a lower movable platform and an upper movable
spring-loaded anvil. The dial indicator is mounted such that it
measures the upward movement of the springloaded anvil. The golf
ball to be tested is placed in the lower platform, which is then
raised a fixed distance. The upper portion of the golf ball comes
in contact with and exerts a pressure on the springloaded anvil.
Depending upon the distance of the golf ball to be compressed, the
upper anvil is forced upward against the spring.
Alternative devices have also been employed to determine
compression. For example, Applicant also utilized a modified Riehle
Compression Machine originally produced by Riehle Bros. Testing
Machine Company, Philadelphia, Pa., to evaluate compression of the
various components (i.e., cores, mantle cover balls, finished
balls, etc.) of the golf balls. The Riehle compression device
determines deformation in thousandths of an inch under a fixed
initialized load of 200 pounds. Using such a device, a Riehle
compression of 61 corresponds to a deflection under load of 0.061
inches.
Additionally, an approximate relationship between Riehle
compression and PGA compression exists for balls of the same size.
It has been determined by Applicant that Riehle compression
corresponds to PGA compression by the general formula PGA
compression=160- Riehle compression. Consequently, 80 Riehle
compression corresponds to 80 PGA compression, 70 Riehle
compression corresponds to 90 PGA compression and 60 Riehle
compression corresponds to 100 PGA compression. For reporting
purposes, Applicant's compression values are usually measured as
Riehle compression and converted to PGA compression.
Furthermore, additional compression devices may also be utilized to
monitor golf ball compression so long as the correlation to PGA
compression is known. These devices have been designed, such as a
Whitney Tester, to correlate or correspond to PGA compression
through a set relationship or formula.
The first embodiment of the present invention shown in FIG. 1a
provides a mantle layer 15 which entirely covers the core 13. The
mantle 15 is comprised of a hard ionomer or other hard polymer
having a Shore D hardness of about 65 or more and outer cover layer
17 is comprised of a soft ionomer or other elastomer having a Shore
D hardness of about 60 or less.
It has been found that multi-layer golf balls having inner and
outer cover layers exhibit high COR values and have greater travel
distance in comparison with balls made from a single cover
layer.
In addition, the softer outer layers adds to the desirable "feel"
and high spin rate while maintaining respectable resiliency. The
soft outer layer allows the cover to deform more during impact and
increases the area of contact between the club face and the cover,
thereby imparting more spin on the ball. As a result, the soft
cover provides the ball with a balata-like feel and playability
characteristics with improved distance and durability.
For a ball having a diameter of at least 1.70", the diameter of the
core layer C is preferably between 1.20 and 1.660 inches.
The thickness of the mantle layer TM is preferably between 0.020
inches and 0.250 inches and the thickness of the outer cover layer
TC is preferably between 0.020 inches and 0.250 inches.
In the second embodiment shown in FIG. 1b, the mantle layer 15 is
comprised of an ionomer layer which is softer than the outer cover
layer 17 and has a Shore D hardness of 65 or less, most preferably
10-60 and most preferably between 30-60. Outer cover layer is
comprised of an ionomer having a Shore D hardness of about 60 or
more, and preferably between 65 and 68, most preferably between
65-75.
The ball of this embodiment has a relatively low PGA compression of
less than 90 and preferably 80 or less. This ball has good travel
distance and a low spin rate by virtue of the combination of a hard
cover and a soft core and mantle.
In this embodiment, the diameter of the core C is preferably
between 1.20 inches and 1.60 inches, the thickness of the mantle
layer TM is preferably between 0.020 inches and 0.250 inches and
the thickness of the outer cover layer TC is preferably between
0.020 inches and 0.250 inches.
The balls of the third and fourth embodiments shown in FIGS. 1c and
1d, respectively, have the same outer diameter D, core diameter C,
mantle thickness TM, and cover thickness TC, as the balls of the
first and second embodiments. The differences are in the Shore D
hardness of the mantle and cover layers.
In the third embodiment of FIG. 1c, the mantle layer 15 has a Shore
D hardness of about 50 or more and the cover layer 17 has a Shore D
hardness of about 65 or less, so long as the mantle hardness is
greater than the cover hardness.
In the fourth embodiment of FIG. 1d, the mantle layer 15 has a
Shore D hardness of about 65 or less and the cover layer has a
Shore D hardness of about 55 ore more, so long as the cover
hardness is greater than the mantle hardness.
Referring to FIG. 3, there is shown a ball having the enlarged
dimensions of the present invention and having a dimple pattern
including 422 dimples, which includes dimples of the three
different diameters and depths measured in accordance with FIG. 2.
As indicated in FIG. 3, the largest dimple 33 diameter is 0.169
inch, with a dimple depth of 0.0123 inch, the intermediate dimple
35 diameter is 0.0157 inch with a dimple depth of 0.0124, and the
smallest dimple 31 diameter is 0.145 inch with a dimple depth of
0.0101 inch. With the pattern shown, the resultant weighted average
dimple diameter is 0.1478 inch and the weighted average dimple
depth is 0.0104 inch. With this configuration and dimple size,
78.4% of the surface area of the ball is covered by dimples,
without any dimple overlap. The ball of FIG. 3 includes repeating
patterns bounded by lines 15, 17, and 19 about each hemisphere,
with the hemispheres being identical. One of such patterns is shown
in FIG. 5, which indicates the arrangement of dimples and the
relative sizes of the dimples in that particular pattern.
A further modification is shown in FIG. 4. This golf ball has 410
dimples comprising 138 dimples having a diameter of 0.169 inch and
a depth of 0.0116 inch, 160 dimples having a diameter of 0.143 inch
and a depth of 0.0101 inch, and 112 dimples having a diameter of
0.112 inch and a depth of 0.0077 inch. The configuration of the
dimples comprises a dimple-free equatorial line E--E dividing the
ball into two hemispheres having substantially identical dimple
patterns. The dimple pattern of each hemisphere comprises a first
plurality of dimples extending in four spaced clockwise arcs
between the pole and the equator of each hemisphere, a second
plurality of dimples extending in four spaced counterclockwise arcs
between the pole and equator of each hemisphere, and a third
plurality of
dimples filling the surface area between the first and second
plurality of dimples. In this ball, none of the dimples overlap.
This pattern provides a weighted average dimple diameter of 0.1433
inch, weighted average dimple depth of 0.010 inch, and a 73.1%
coverage of the surface of the ball.
A still further modification is shown in FIG. 5. This golf ball has
422 dimples all dimples having the same diameter of 0.0143 inch and
the same depth of 0.0103 inch. The dimples are arranged in a
configuration so as to provide a dimple-free equatorial line, with
each hemisphere of the ball having six identical dimpled
substantially mating sections with a common dimple at each pole.
FIG. 5 shows two mating sections having dimples 1 and 2,
respectively. Each section comprises six dimples lying
substantially along a line parallel with, but spaced from, the
equatorial line, 29 dimples between the six dimples and the common
polar dimple, with the outer dimples of each of the sections lying
on modified sinusoidal lines 113 and 115.
Since only one diameter is used for all dimples, some small
percentage of overlap occurs in order to provide substantial
surface coverage with the dimples. For this particular pattern,
there is an 11.4% (48) dimple overlap with a 73.2% coverage of the
surface of the ball. Overlap is determined by finding the number of
dimples having an edge overlapping any other dimple and dividing
that number by the total number of dimples on the ball, such number
being expressed as a percentage. Other dimple patterns can be used
which provide a 65% or greater coverage on the surface of the
ball.
In addition to the advantages discussed above there is easier
access to the ball with the club in both the fairway and rough
because of the ball's size. This easier access allows for cleaner
hits. Further, the increased size and moment results in the ball's
ability to hold the line during putting. Thus, by increasing the
percentage of dimple coverage of the surface of the ball, the ball
has the advantages attributable to the larger ball while having
enhanced flight characteristics as compared to previous balls
having enlarged diameters.
The above description and drawings are illustrative only since
obvious modifications could be made without departing from the
invention, the scope of which is to be limited only by the
following claims.
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